This is my understanding of the way the war developed in the 1780s:|
The Colonial Army was pressuring the British in New York City just by their presence nearby. The British split up their army. Clinton sent Cornwallis and half of the army south where they created some pressure on colonial forces in the Carolinas. Then the French entered the war. Clinton sent a message to Cornwallis that he wanted Cornwallis to find a port where the British Navy could harbor. Cornwallis chose Yorktown. The problem was that it was a port that could be blockaded by the French Navy, but Cornwallis had complete confidence in the British Navy. They had always been able to handle the French. What he didn't know was that the British Navy was spread thin. They had to defend Britain from invasion, and they had to defend India. Washington left a small force outside of New York City, and he slipped away from NYC with a large portion of the colonial army. They marched down from NYC, through New Jersey, and stopped at Mt. Vernon. They arrived near Yorktown without being detected, and they immediately started digging siege trenches. Cornwallis had assigned his troops a line of defense, and they were instructed to remove all trees and buildings within a certain distance of his line. The French took the left side of the allied line, and the Americans took the right. The bombardment started. The allied cannon gradually destroyed the British cannons. They also continued to dig trenches to get closer to the British lines. The French Navy drove off a British Naval force, and the vice started to close. Cornwallis's only option was to evacuate his army to Glouster. The first group of soldiers made it, but a storm blew up, and his small boats were destroyed. He had no option other than negotiate terms of surrender.